The invention concerns a heating system or air conditioning system for vehicles. More specifically, the invention relates to heating systems or air conditioning systems of the type having an air box such as a heater box and an operator unit for at least one control unit such as an air distribution flap, which operator unit has to be arranged separately from the air box in the passenger compartment such as at an instrument panel, the operator unit being connected to the air box by means of a control line leading to the control unit, and having a two-part assembly aid element of which one part is firmly connected to the air box and the other part is firmly connected to the operator unit, the two parts being put together in the pre-assembly condition to hold the operator unit on the air box and being pulled apart after installation of the air box for the purpose of placing the operator unit at the installation location.
In such heating systems or air conditioning systems, manual operator actions are undertaken at the operator unit and these operator actions are transmitted via the control line to the at least one control unit integrated in the air box and there lead to corresponding adjustment or switching procedures.
An example of such an adjustment procedure is the adjustment of air distribution flaps in the heater box, as is described in German Patent Document DE 39 36 776 C1. In this case, the operator unit is accommodated in an operator surface, for example the dashboard or the instrument panel of the motor vehicle, and is connected via a universal joint arrangement to at least one pivoting lever for the air distribution flaps. The pivoting lever is pivotably supported on the heater box. The pivoting lever and air distribution flaps form the at least one control unit previously mentioned and, in this case, the control unit controls the air distribution corresponding to the adjustment undertaken at the operator unit. The manually initiated rotary motions of a rotary knob on the operator unit are transmitted via the universal joint arrangement to the pivoting lever and lead to the desired adjustment of the air distribution flaps. In order to compensate for tolerances in the path of motion, the link rod of the universal joint arrangement is of telescopic configuration and its two telescopic parts are guided so that they cannot be rotated relative to one another but can be axially displaced relative to one another.
Such heating systems and air conditioning systems are supplied as adjusted installation units for installation in the motor vehicle so that adjustment work becomes unnecessary during assembly. In order to hold the adjusted operator unit on the heater box until final assembly, the heater box and the operator unit are firmly connected to each other after adjustment by means of the two-part assembly aid element. In a known heating system or air conditioning system, the assembly aid element is embodied as a U-shaped retention shackle which is fastened to two holders attached to the heater box, to be precise to the side facing the operator unit. The transverse web of the holder carries the operator unit and the two arms of the shackle connected to each other by means of the transverse web are engaged in each of the two holders. During assembly, the heater box is first installed in the vehicle so that the operator unit comes to rest at a small distance in front of its final installation location. After the assembly of the operator surface, for example the dashboard or the instrument panel, the retention shackle together with the operator unit is pulled onto the back of the operator surface and is fastened to the latter. During this procedure, the arms of the U-shaped retention shackle are withdrawn from the two holders and the operator unit is disconnected from the heater box. Because of the inaccessibility of the installation space between the side of the heater box facing towards the operator unit and the back of the operator surface, the holder and retention shackle are not removed and remain at the installation location.
An object of the invention is to improve the assembly aid for connecting the operator unit and the heater box in the pre-assembly condition in a heater system or air conditioning system of the type mentioned above in such a way that simple and low cost manufacture is achieved.
The object is achieved in a heating system or air conditioning system of the generic type mentioned above by providing an arrangement wherein the two parts of the assembly aid element are formed by two plug-in parts of a plug-in connection which can be plugged one into the other and wherein a clip-type interlock is attached to the plug-in connection, which clip-type interlock which is engaged by axial pressure on the plug-in parts and can be released by axial tension on one of the plug-in parts.
The heating system or air conditioning system according to the invention has the advantage that only one single part remains necessary for the assembly aid element on the heater box and this part can, if need be, be removed as desired from the heater box after the completion of assembly. In addition, this part can be manufactured as a low-price plastic part. The connection and disconnection of the operator unit and the heater box can be carried out rapidly by simply plugging in and pulling apart, respectively. An interlock prevents unintentional separation of the plug-in connection before final assembly.
Advantageous embodiments of the heating system or air conditioning system according to the invention with desirable further developments and embodiments of the invention are given in the further claims.
In a preferred embodiment of the invention, one plug-in part is designed as a plug-in sleeve and the other as a plug-in peg which can be pushed into it. The interlock consists of an engagement hole in one plug-in part and a spring engagement tongue with an engagement lug protruding from it on the other plug-in part. The engagement lug is provided with two lift-out bevels diametrically opposite to one another in the plug-in direction of the plug-in parts. On the one hand, these bevels permit the engagement lug to be pushed onto one plug-in part and, on the other, they permit the engagement lug to be lifted out of the engagement hole of this plug-in part.
In a preferred embodiment of the invention, the plug-in sleeve is configured on the back of the operator unit, preferably integrally with its casing, and the plug-in peg is configured on the free end of a connecting arm, preferably integrally with the latter, the arm being releasably fastened to a position on the heater box which is accessible after the final assembly of the heater box in the vehicle. This design embodiment has the advantage that the arm carrying the plug-in peg, which is the more voluminous and--in terms of manufacturing costs--the more expensive part of the assembly aid element, can be removed after the installation of the heating system or air conditioning system in the motor vehicle and, if need be, can be used again in the pre-assembly of further heating systems or air conditioning systems. The dimensions of the plug-in sleeve which cannot be released and remains on the operating unit can be kept so small that the continued presence of the sleeve does not hinder other installation measures.
In accordance with a further embodiment of the invention, the spring engagement tongue of the interlock is arranged on the plug-in peg, being fixed by the base of the tongue on the plug-in peg and extending towards the free end of the plug-in peg parallel to and at a distance from the latter which is slightly larger than the wall thickness of the plug-in sleeve. The engagement lug projects from the engagement tongue towards the plug-in peg and the engagement hole is embodied as a drilled hole in the plug-in sleeve. This design measure also contributes to the fact that the plug-in sleeve, which remains on the operator unit after final assembly, is kept very simple from the manufacturing point of view and that all the more expensive manufacturing measures occur on the plug-in peg. Because the arm carrying the plug-in peg is removed and can be reused after final assembly of the heating system or air conditioning system, it is only necessary to hold a limited stock of the more expensive part of the assembly aid element. This further reduces the manufacturing costs.
In order to avoid loss of adjustment of the heating system or air conditioning system after preassembly, a rotational lock is provided, in accordance with a further embodiment of the invention, to prevent relative rotation between the two plug-in parts. The rotational lock can be realized for example by an axial groove machined into one plug-in part and an axial rib on the other plug-in part which can be pushed as a form fit into the axial groove. Rotational locking is, however, also achieved by the fact that the plug-in sleeve and the plug-in peg are embodied with rectangular cross-section.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.